The present invention relates to an image reading apparatus and an image input-output apparatus.
Generally, a flat-bed type image reading apparatus is known, which is provided with a transparent, plate-shaped original table, for putting an object thereon, on an upper surface of a body of the apparatus as a apparatus reading an optical image of the object.
Generally, the flatbed type image reading apparatus is provided with a guide member, for positioning an object on a board surface of the original table by attaching the object thereto, which is jointed to surrounding edge portions of the original table. In the image reading apparatus, inside of a rectangle area whose vertex is defined as a reading origin setting a position by employing edge sides of the guide member as a standard is set as a reading area, and image data representing an optical image in the area is outputted.
Incidentally, in the above-mentioned image reading apparatus, it is difficult to completely remove stagger of main scanning line by completely removing looseness of a carriage installing an image sensor etc. and a guide thereof. In light of such the circumstances and producing allowance, in order to prevent that a picture of the guide member itself passing the reading area set on the board surface of the original table is outputted as an image data, the reading origin of the object is set to a position slightly separated from edge sides of the guide member on the board surface of the original table.
However, since the reading area is set to inner side of the original table than the edge sides of the guide member by separating the reading origin from the edge sides of the guide member, the surrounding edge portions of the object can not be read even by attaching the object such as paper document and the like to the edge sides of the guide member closely. Therefore, it is desirable to set the reading origin as close as the edge sides of the guide member. The reading origin in the general image reading apparatus is set to the position separating about 3 mm respectively from edge sides of two guide members crossing each other at a right angle.